An intake air cooling apparatus abnormality detection system for an engine includes a first intake air temperature sensor that detects an intake air temperature in an intake pipe at the downstream side of an intercooler and a second intake air temperature sensor that detects the intake air temperature in an intake manifold. An abnormality determination unit determines that an abnormality occurs in an intercooler cooling water circuit if a state in which at least one of a value based on an output from the first intake air temperature sensor and a value based on an output from the second intake air temperature sensor exceeds a predetermined threshold value continues for a certain time or longer when a load state determination unit determines that the engine is in a high load state.